A low wt. resistant porous glass fiber with a developed sp. surface area of 5-120 times the outer surface of a std. glass fiber, and a material having phys., chem. or biol. reactive properties deposited on the developed surface area of porous glass fiber are described. Another low wt. resistant porous glass fiber with a developed sp. surface area of 20-200 times the outer surface of a std. glass fiber is presented. The developed surface of porous glass fiber is coated with a support material for a material which has phys., chem. or biol. reactive properties and which is deposited on the intermediate support material covering the porous glass fiber. Corresponding prepn. processes and various uses are described. [on SciFinder (R)]